U-Bolts are a single-use style of bolt that holds the axle to the leaf spring assembly. The top of the leaf spring assembly typically attaches to the frame of the vehicle. Keepers, or Retainer Clips, keep the leaves within the leaf spring pack from moving side to side.
U-bolts can have different shapes, but the most common are; round, semi-round, or squared. They come in different diameters and lengths so we take precise measurements to ensure you are getting the exact fit and strength you need for your application.
Our steel U-Bolt bar-stock is American-made and is bent to order which allows us to control the highest quality standards and to ensure the customer is getting their exact spec.
U-bolts cannot be re-used because a previously torqued U-bolt will suffer from distorted threads from engagement of the deep nut. Deep nuts should be tightened and re-torqued, never loosened and re-tightened. Our competitors typically use cheap, foreign, pre-made U-bolts which are lower quality and that may not be the right dimensions. Customers may be stuck as to many companies do not accept returns on U-Bolts. Our goal is to provide the best parts and customer service, which is why we make each U-Bolt to order and to the exact specifications.
About U-Bolts
U-bolts are critical fasteners used in leaf spring style suspension systems of trailers as well as trucks. Typically shaped like the letter “U,” they secure the leaf springs to the axle. “U-bolts” can be round, square, semi round, or a unique radius per the specific application. Trailer U-bolts are typically round or square bend types. The diameter of the rod used in trailer U-bolts are typically 1/2” or 9/16” but lighter duty trailers can be 7/16”.
It is highly recommended to verify the torque on U-bolts after installation after approximately 500 miles due to the possibility of the threads “stretching” and the suspension “settling”. U-bolts are recommended to be one-time use because they are “torque-to-yield” meaning that the threads are designed to stretch and slightly deform, binding into the tall nut thus locking it into place. This deformation cannot be detected by the naked eye and plays into the “plate-pressure rating” that is achieved through the torquing process. Loose U-bolts can result in excessive vibration and even movement. This puts additional strain on especially the spring center-bolt which can cause it to bend or break.
John’s Spring and Suspension custom bends U-bolts to customer specifications. For any questions on how to measure and order the correct U-bolts, call us today at (775) 329-6159.
